The invention pertains generally to a cutting tool mounting assembly that is useful in association with machines for impinging a substrate or earth strata such as, for example, asphaltic roadway material, coal deposits, mineral formations and the like. More particularly, the invention pertains to a cutting tool mounting assembly as well as the individual components of such assemblies.
One typically uses such assemblies in conjunction with a rotatable drum or driven member. The driven member rotates in such a fashion to drive the rotatable cutting bit or tool into earth strata to disintegrate the same into smaller pieces including fine particulates, i.e., cutting debris. The cutting bit or cutting tool and the base or support block are each subjected to considerable stresses during mining operations, road milling operations or other like operations that can lead to wear and/or failure of one or more of the cutting tool assembly components. One source of wear occurs as a result of the mounting between the cutting bit or cutting tool and the base or support block and the contact therebetween. Accordingly, there is a desire to mount the cutting bit or cutting tool in the base or support block so as to reduce stress between the components in order to maximize the useful life of all the components of the cutting tool assembly.
One solution to minimize such stress and/or wear is to provide a bushing between the cutting bit or cutting tool and the base or support block. Typically, the bushings are press fit into the base or support block which after a long time of operation they can begin to rust together and become very difficult to remove. An alternative to the bushing arrangement is to use a sleeve which is a slip fit into the base or support block and held in with an external retainer. These are easier to remove but cause the base or support block to wear quicker.
Thus, it would be highly desirable to provide an improved cutting tool mounting assembly that overcomes disadvantages and shortcomings of heretofore known such assemblies. It would also be highly desirable to provide an improved cutting tool mounting assembly having a bushing arrangement that is easier to remove while still providing the desired protection to the base or support block in comparison to heretofore known such arrangements.